As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
ON SELECTION OF GEAR UP AFTER TAKEOFF, THE LANDING GEAR FAILED TO RETRACT AND THE NR 2 HYD ISO VLV CAUTION LIGHT ILLUMINATED. EMERGENCY DECLARED AND AIRCRAFT RETURNED TO OGG. (MX) REPLACED THE NLG DOOR SOLENOID SEQUENCE VALVE. NOTE: 2 OF 4 HOUSING BOLTS ON THE SOLENOID VALVE FAILED.